<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script>
        var money = '$20';b=[]
        // write your code here...
        for(var i=0;i<money.length;i++){
            if(money[i]>='0'&&money[i]<='9'){
                b.push(money[i])
            }
        }
        b=b.join('')
        console.log(b)
    </script>
</head>
<body>

</body>
</html>